1. Field of the Invention
This invention is in the field of adjustable punch presses for applying to each segment of a strip of such segments data identifying, for example, the integrated circuit chip mounted on the leads of a lead pattern of such a segment.
2. Description of the Prior Art
The development of integrated circuits (IC) chips, particularly medium and large scale IC chips has created the need for improved manufacturing processes to automate the bonding of such chips on substrates or in individual packages. It is known to attach IC chips to lead frames formed on a relatively long strip of a tape-like carrier similar to standard motion picture film. The lead patterns are formed from a thin metallic layer of a good electrical conductor such as copper which is bonded to the film. The strip, typically 35 mm wide, is divided into segments, typically two segments for each 35 mm of length of the strip. The layer of copper of each segment is formed into a lead pattern of a desired configuration by conventional photoetching processes. Each segment is provided with a window over which the leads of the lead pattern extend. Subsequently the IC chips are bonded to ends of the leads extending over the window of a segment. The lengths of such strips of film are such that to facilitate handling and shipping the strips of film with an IC chip secured to the leads of each lead pattern, are wound on reels. As a general rule IC chips of the same type are mounted on the segments of a given film strip.
To facilitate handling the segments and their attached IC chips prior to the chips and their leads being excised from the segments, the segments of a strip are separated by cutting the strip at segment boundaries which separate the segments from one another. The separated and individual segments are then mounted in a fixture such as is disclosed in U.S. Pat. No. 4,007,479 which issued on Feb. 8, 1977 or in U.S. Pat. No. 4,067,496 which issued on Jan. 17, 1978.
As mentioned above, as a general rule, IC chips of the same type are bonded to the leads of segments of a given strip, and information indentifying the chips is marked on the reel on which the strip is wound for example. When segments of a given type are mounted on non-reusable fixtures such as are illustrated in FIG. 2 of U.S. Pat. No. 4,007,479, indicia, or data, identifying the chip held by the fixture, the source of the chip for example and other relevant information can be printed on the outer surface of the fixture.
As reusable fixtures such as those illustrated in U.S. Pat. No. 4,069,496 have replaced nonreusable fixtures, particularly in high volume production situations, a way of identifying the chip mounted on a given segment and relevant data with respect to the chip is needed which is independent of the fixture or holder. No prior art apparatus for applying such identification data to a segment carrying such a chip is known to the applicant.
It is important that the identification data be machine readable so that record keeping can be automated; that applying such data and its presence on the segment not have any adverse impact on subsequent manufacturing steps and processes used in mounting the chip and its leads on a substrate or in a package; and that there be no damage to the chip and its leads. While the data for each chip attached to the segments of a given film strip are generally the same and therefore the identification data applied doesn't change for a given film strip, nevertheless the apparatus for applying the data must be easily changeable by an operator prior to applying the appropriate identification data, for example, to each segment of a strip of film sufficiently early in the manufacturing process so that the possibility of errors in identifying the chips of that strip cannot occur.